1. Field of the Invention
The present invention relates generally to handlebar assemblies for vehicles such as motorcycles and all-terrain vehicles (atv's). More specifically, the present invention relates to an improved handlebar assembly, including a shock absorbing arrangement.
2. Description of the Related Art
Motorcycles and atv's, among other vehicles, commonly incorporate a handlebar assembly to assist in the steering of the vehicle. The handlebar assembly is usually mounted to the front wheel through a front suspension assembly. The handlebar is often an elongated, tubular member that extends in a generally lateral direction and includes a handgrip portion at each end, for a rider of the vehicle to grasp. Such an arrangement also provides a means of support for a portion of the rider's body weight, especially when in a standing position.
In the case of off-road motorcycles and atv's, the vehicle is likely to traverse rough terrain, including jumps, on a regular basis. Unless adequately absorbed, forces imparted on the vehicle due to the rough nature of the terrain may be transmitted to the rider through the handlebar assembly and foot rests, or footpegs, of the motorcycle. This may cause undesirable fatigue and result in the rider having reduced control of the vehicle. Such a situation is especially undesirable in motorcycle or atv racing, in which maintaining a consistent pace throughout the event is necessary in order to be competitive.
In order to absorb at least a portion of the impact forces caused by traversing rough terrain, motorcycles and ATVs are commonly equipped with front and rear suspension assemblies operably positioned between the front and rear wheel, or wheels, and the main body of the vehicle. Such suspension assemblies, due to inherent design constraints, are only capable of absorbing impact forces within a finite range of magnitude and/or frequency. Accordingly, impact forces outside of this range may be transmitted to the rider of the vehicle, through the handlebar assembly, despite the proper functioning of the front and rear suspension assemblies. For example, an impact force having an amplitude large enough to fully compress either, or both, of the front and rear suspension assemblies may result in the remainder of the force being transmitted to the rider. In other situations, an impact force having a high frequency may not be adequately absorbed by the suspension assemblies, often due to internal friction inherent to common shock absorber designs, which may be caused by sealing arrangements and/or movement of hydraulic fluid.
Accordingly, some prior handlebar assemblies have been designed to possess a certain amount of flexing movement. For example, the handlebar may be made from a material that possesses inherent flexibility to absorb at least a portion of the impact forces that would otherwise be transmitted to the rider. More recently, handlebars have been produced with a varying wall thickness to encourage flexing of the outer ends, or handgrip portions, of the handlebar. However, manipulation of the handlebar material in order to create a varying wall thickness causes the final product to be expensive. Furthermore, in order to maintain the necessary strength of the handlebar assembly, the flex of the handgrip portions is necessarily limited to a small amount of movement and, thus, a small amount of shock absorbing capability.
Finally, with this type of handlebar arrangement, the direction of movement during flexing of the handgrip portions is not controlled. That is, the handgrip portions are permitted to flex in all directions. Accordingly, the amount of advantageous, shock absorbing flex (i.e., generally downward flex of the handgrip portions) is limited by the amount of flex that is permissible in the other directions while still providing a handlebar assembly having a solid feel. As a result, the amount of shock absorbing flex permitted in these types of handlebar assemblies is compromised by the need for the handlebar assembly to provide a solid feel when a rider is pulling in an upward or backward direction on the handgrip portions, which is common during acceleration of the motorcycle or atv.